What are my best options before OCS?

If you get to go to Federal OCS as a member of the Guard then your branch is already determined by your state and you can only enter into a branch that your state has (Officers don’t have MOS’s, it’s called a branch). For example a buddy of mine is in the NH Guard and is a logistician. He came to Federal OCS already knowing his branch because it was assigned to him at his state. So you can’t enter into a branch that your state doesn’t have a unit for. So one way to go about becoming an Armor Officer is to transition into active duty then apply for OCS. There is no real reason to go to Armor AIT first, it won’t necessarily help you. Another option is to transfer to a state that has Armor officers and then apply for OCS, but be aware that at the State level the chances of getting Federal OCS are very slim, it is very competitive. The only other option I can think of is to finish your contract with the Guard and then go through the process of requesting OCS through an Active Duty recruiter. If you need more info or have more questions shoot me a PM, I’m Cadre at 3-11 IN which is OCS.

If you want to be an officer, the sooner you start, the better.

I am a Armor Officer at the Armor Basic Officer Leadership Course. If I was in your shoes in would stay guard, pick Armor as your branch/branches, and then go from there. You can delay your commission for 2 years to hold out for the branch you want. Once you graduate ABOLC you can do the Call to Active Duty (CAD) and go active. That is what I am currently doing to do as well.